Mag

Distribution by Scientific Domains
Distribution within Physics and Astronomy


Selected Abstracts


The Male Accessory Gland Substances of Lucilia illustris (I): Its Effect on Mating Receptivity

ENTOMOLOGICAL RESEARCH, Issue 2 2002
Jong-Jin LEE
ABSTRACT In order to verify the physiological functions of male accessory gland (MAG) substances of the blowfly, Lucilia illustris Meigen, the growth and changes in metabolites of male accessory gland with aging, and the effect of male accessory gland extract on mating receptivity of L. illustris were examined. There was not a significant difference in length of MAG with aging, but the width of MAG was grown widely from 0 to 5-days old apparently. Changes in glycogen, total protein and lipid of male accessory gland substances showed same patterns but total protein content was higher than the others. Therefore, male nutrition affected the production of male accessory proteins. During the mating fed unmated male transferred larger amount of protein than that of starved male. When male accessory gland homogenates injected, mating receptivity of gravid female was greatly inhibited comparing to control, suggesting that the accessory gland substances of L. illustris alters female mating receptivity after mating. [source]


A New Brand in Imaging

IMAGING & MICROSCOPY (ELECTRONIC), Issue 1 2008
Five Imaging Companies Formed MAG In Late 200
The Microimaging Applications Group (MAG) comprises five imaging technology leaders: Gatan, Media Cybernetics, Photometrics, QImaging, and MAG Biosystems. These partners work independently as well as in synergy to offer an unparalleled range of solutions for microimaging applications. Michael Reubold spoke with Steven Ridge, MAG's Vice President of Marketing about the concept and strategy behind the formation of MAG. [source]


Study of peptide,sugar non-covalent complexes by infrared atmospheric pressure matrix-assisted laser desorption/ionization

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2004
Christopher E. Von Seggern
Abstract Infrared atmospheric pressure matrix-assisted laser desorption/ionization quadrupole ion trap mass spectrometry was applied to the study of siglec binding to oligosaccharide ligands. Peptides were designed to mimic the binding sites of three members of the siglec family: sialoadhesin, MAG and CD22. These peptides were tested for their ability to complex with their carbohydrate ligands 3, -sialyllactose (3,SL) and 6, -sialyllactose (6,SL). All peptides demonstrated the ability to bind to the carbohydrates, with the peptide representing sialoadhesin maintaining its binding specificity for 3,SL in preference to 6,SL. This technique can be used to study other protein,sugar interactions and can be expanded to create high-throughput screening techniques. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Characterization of two novel proteins, NgRH1 and NgRH2, structurally and biochemically homologous to the Nogo-66 receptor

JOURNAL OF NEUROCHEMISTRY, Issue 3 2003
V. Pignot
Abstract Nogo-66 receptor (NgR) has recently been identified as the neuronal receptor of the myelin-associated proteins Nogo-A, oligodendrocyte protein (OMgp) and myelin-associated glycoprotein (MAG), and mediates inhibition of axonal regeneration both in vitro and in vivo. Through database searches, we have identified two novel proteins (NgRH1 and NgRH2) that turned out to be homologous in their primary structures, biochemical properties and expression patterns to NgR. Like NgR, the homologues contain eight leucine-rich repeats (LRR) flanked by a leucine-rich repeat C-terminus (LRRCT) and a leucine-rich repeat N-terminus (LRRNT), and also have a C-terminal GPI signal sequence. Northern blot analysis showed predominant expression of NgRH1 and NgRH2 mRNA in the brain. In situ hybridization and immunohistochemistry on rat brain slices revealed neuronal expression of the genes. NgRH1 and NgRH2 were detected on the cell surface of recombinant cell lines as N-glycosylated GPI anchored proteins and, consistent with other GPI anchored proteins, were localized within the lipid rafts of cellular membranes. In addition, an N-terminal proteolytic fragment of NgR comprising the majority of the ectodomain was found to be constitutively secreted from cells. Our data indicate that NgR, NgRH1 and NgRH2 constitute a novel receptor protein family, which may play related roles within the CNS. [source]


Sema4D deficiency results in an increase in the number of oligodendrocytes in healthy and injured mouse brains

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 13 2009
Yoshitaka Taniguchi
Abstract Semaphorins, a family of secreted and membrane-bound proteins, are known to function as repulsive axon guidance molecules. Sema4D, a class 4 transmembrane-type semaphorin, is expressed by oligodendrocytes in the central nervous system, but its role is unknown. In this study, the effects of Sema4D deficiency on oligodendrocytes were studied in intact and ischemic brains of adult mice. As observed in previous studies, Sema4D marked by ,-galactosidase in Sema4D mutant mice was localized exclusively on myelin-associated glycoprotein (MAG)-positive oligodendrocytes but not on NG2-positive oligodendrocyte progenitor cells (OPCs). Although there was no difference in the number of the latter cells between Sema4D-deficient and wild-type mice, the number of MAG-positive cells was significantly increased in the cerebral cortex of both nonischemic and postischemic brains of Sema4D-deficient mice. Cell proliferation, observed by using bromodeoxyuridine incorporation, was evident in the MAG-positive cells that developed after cerebral ischemia. These data indicate that Sema4D is involved in oligodendrogenesis during development and during recovery from ischemic injury. © 2009 Wiley-Liss, Inc. [source]


Myelin proteolipid protein, basic protein, the small isoform of myelin-associated glycoprotein, and p42MAPK are associated in the Triton X-100 extract of central nervous system myelin

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2002
Dina N. Arvanitis
Abstract To further our understanding of the functions of the major myelin proteins, myelin basic protein (MBP) and proteolipid protein (PLP), and other myelin proteins, such as 2,3,-cyclic nucleotide 3,-phosphodiesterase (CNP) and myelin-associated glycoprotein (MAG), bovine brain myelin was extracted with Triton X-100, and protein complexes in the detergent-soluble fraction were isolated by coimmunoprecipitation and sucrose density gradient sedimentation. MBP, PLP, and the small isoform of MAG (S-MAG) were coimmunoprecipitated from the detergent-soluble fraction by anti-PLP, anti-MBP or anti-MAG monoclonal antibodies. Additionally, a 30 kDa phosphoserine-containing protein and two phosphotyrosine-containing proteins (Mr 30 and 42 kDa) were found in the coimmunoprecipitates. The 42 kDa protein is probably p42MAPK, in that MAPK was shown also to be present in the immunoprecipitated complex. CNP, the small PLP isoform DM20, the large MAG isoform L-MAG, MOG, CD44, MEK, p44MAPK, and actin were not present in the immunoprecipitates, although they were present in the detergent-soluble fraction. Lipid analysis revealed that the PLP,MBP,S-MAG coimmunoprecipitated with some phospholipids and sulfatide but not cholesterol or galactosylceramide. However, the complex had a high density, indicating that the lipid/protein ratio is low, and it was retained on a Sepharose CL6B column, indicating that it is not a large membrane fragment. Given that MAG is localized mainly in the periaxonal region of myelin, where it interacts with axonal ligands, the PLP,MBP,S-MAG complex may come from these regions, where it could participate in dynamic functions in the myelin sheath and myelin,axonal interactions. © 2002 Wiley-Liss, Inc. [source]


Core-shell particles with glycopolymer shell and polynucleoside core via RAFT: From micelles to rods

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2009
Samuel Pearson
Abstract Amphiphilic block copolymers were synthesized via the reversible addition fragmentation chain transfer (RAFT) copolymerisation of 2-methacrylamido glucopyranose (MAG) and 5,- O -methacryloyl uridine (MAU). Homopolymerisations of both monomers using (4-cyanopentanoic acid)-4-dithiobenzoate (CPADB) proceeded with pseudo first order kinetics in a living fashion, displaying linear evolution of molecular weight with conversion and low PDIs. A bimodal molecular weight distribution was observed for PMAU at low conversions courtesy of hybrid behavior between living and conventional free radical polymerization. This effect was more pronounced when a PMAG macroRAFT agent was chain extended with MAU, however, in both cases, good control was attained once the main RAFT equilibrium was established. A stability study on PMAU found that its hydrolysis is diffusion controlled, and is accelerated at physiological pH compared with neutral conditions. Self-assembly of four block copolymers with increasing hydrophobic (PMAU) block lengths produced micelles, which demonstrated an increased tendency to form rods as the PMAU block length increased. Interestingly, none of the block copolymers were surface-active. An initial assessment of PMAU's ability to bind the nucleoside adenosine through base pairing was highly promising, with DSC measurements indicating that adenosine is fully miscible in the PMAU matrix. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1706,1723, 2009 [source]


Sex-dimorphic effects of progesterone and its reduced metabolites on gene expression of myelin proteins by rat Schwann cells

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2006
Valerio Magnaghi
Abstract Data obtained in our and other laboratories have indicated that progesterone (P) and its derivatives, dihydroprogesterone (DHP) and tetrahydroprogesterone (THP), stimulate the expression of two myelin proteins of the peripheral nervous system (PNS) [i.e., glycoprotein zero (P0) and peripheral myelin protein 22 (PMP22)]. We have now considered the effects of P and its derivatives on these and other myelin proteins [i.e., myelin-associated glycoprotein (MAG) and myelin and lymphocyte protein (MAL)] in sex-specific cultures of rat Schwann cells. Gene expression of myelin proteins was assessed by RNase protection assay. Treatment with P or DHP induced a stimulatory effect on P0 mRNA levels in male but not in female Schwann cells. In contrast, treatment with THP increased gene expression of P0 exclusively in female Schwann cells. A similar sex-difference was also evident for other myelin proteins. Indeed, PMP22 expression was stimulated by treatment with P in male cultures, whereas THP induced an increase of mRNA levels in female cultures. Moreover, MAG was stimulated by THP treatment in male cultures only, whereas MAL expression was unaffected by neuroactive steroid treatment in both male and female cultures. In conclusion, the present observations indicate that the effects of neuroactive steroids on myelin proteins are sexually dimorphic. This finding might represent an important background for sex-specific therapies of acquired and inherited peripheral neuropathies. [source]


MYELIN PROTEIN P-0-SPECIFIC IGM PRODUCING MONOCLONAL B CELL LINES WERE ESTABLISHED FROM POLYNEUROPATHY PATIENTS WITH MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE (MGUS)

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 4 2002
M Kvarnstrom
Monoclonal expansion of B cells and plasma cells, producing antibodies against ,self' molecules, can be found not only in different autoimmune diseases, such as peripheral neuropathy (PN), but also in malignancies, such as Waldenstroms'macroglobulinaemia and B-type of chronic lymphocytic leukaemia (B-CLL), as well as in precancerous conditions including monoclonal gammopathy of undetermined significance (MGUS). About 50% of patients with PN-MGUS have serum antibodies against peripheral nerve myelin, but the specific role of these antibodies remains uncertain. The aims of the study were to establish, and characterize, myelin-specific B cell clones from peripheral blood of patients with PN-MGUS, by selection of cells bearing specific membrane Ig-receptors for myelin protein P-0, using beads coated with P-0. P-0-coated magnetic beads were used for selection of cells, which subsequently were transformed by Epstein-Barr virus. The specificity of secreted antibodies was tested by ELISA. Two of the clones producing anti-P-0 antibodies were selected and expanded. The magnetic selection procedure was repeated and new clones established. The cells were CD5(+) positive, although the expression declined in vitro over time. The anti-P-0 antibodies were of IgM-lambda type. The antibodies belonged to the V(H)3 gene family with presence of somatic mutations. The IgM reacted with P-0 and myelin-associated glycoprotein (MAG), and showed no evidence for polyreactivity, in contrast to other IgM CD5(+) clones included in the study as controls. The expanded clones expressed CD80 and HLA-DR, which is compatible with properties of antigen-presenting cells. The immunomagnetic selection technique was successfully used for isolation of antimyelin protein P-0-specific clones. The cell lines may provide useful tools in studies of monoclonal gammopathies, leukaemia, and autoimmune diseases, including aspects of antigen-presentation by these cells followed by T cell activation. [source]


Physico-enzymatic production of monoacylglycerols enriched with very-long-chain polyunsaturated fatty acids

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2008
Ratchapol Pawongrat
Abstract BACKGROUND: Monoacylglycerols (MAG) containing polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have interesting applications. The enzymatic processing of such MAG directly from fish oils is highly interesting, integrating the processing of MAG and concentration of EPA and DHA. The aim of this study was to develop an efficient enzymatic glycerolysis system together with physical fractionation for the production of PUFA-MAG from tuna oil. RESULTS: Novozym 435 was eventually selected after evaluation together with immobilized lipase AK in a tertiary alcohol-based system. A further evaluation of solvent mixtures involving tertiary alcohols was made, taking ease of operation into consideration. It turned out that a number of mixtures gave a similar performance to that of tert -butanol (TB). Basic reaction parameters were thoroughly evaluated. In the batch reaction system with TB as solvent, the recommended conditions were: glycerol/tuna oil 4:1 (mol/mol), TB/tuna oil 2:1 (wt/wt), 15 wt% Novozym 435, and temperature 40 °C. Under these conditions, the yield of MAG was up to 90% after 3 h incubation. Crude MAG from the production was fractionated to produce MAG with higher EPA and DHA content. Using acetone as solvent at 0 °C led to ca 50% yield of MAG but contained EPA and DHA up to 71% in comparison with ca 30% in tuna oil. CONCLUSION: Potentially practical process steps have been developed for the production of MAG containing a high content of EPA and DHA from natural fish oils with high efficiency and simplicity. Copyright © 2007 Society of Chemical Industry [source]


Fungal metabolism of butter and shea oils by Penicillium roquefortii in solid state cultures

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2004
Qin-Tao Liu
Abstract Monoacylglycerols (monoglycerides, MAGs) were produced from butter oil and shea stearin fraction (shea oil) by two strains of Penicillium roquefortii, FRR 2456 (isolated from a spoilt melon) and Wisbey PJ (a commercial dairy strain), at pH 7.0 at 10 and 25 °C. The system was designed as a model of cheese using modified Czapek medium in solid state cultures. Shea oil with its unique fatty acid profile (stearic, oleic and palmitic acids) was used for comparison with butter oil. Yields of MAGs, which ranged from 3 to 14 g kg,1 oil, were higher with butter than with shea oil and higher when the spoilage strain FRR 2456 was used. Monoacylglycerols produced by mycelium-bound lipases from both fungal strains were mainly sn -1(3) or , isomers (60,70 mol%). Monopalmitin was the major MAG produced from both butter and shea oils. The production and use of MAGs alone or in combination with free fatty acids (FFAs) as food preservatives are discussed. It is implied that sn -1(3) MAGs together with free fatty acids may be part of a natural antimicrobial system in relatively high-pH foods such as blue mould-ripened cheese where growth of foodborne pathogens such as Listeria monocytogenes can be a problem. Copyright © 2003 Society of Chemical Industry [source]


Female sex pheromone suppression and the fate of sex-peptide-like peptides in mated moths of Helicoverpa armigera

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2007
V.K. Nagalakshmi
Abstract Insect males produce accessory gland (MAG) factors that are transferred in the seminal fluid to females during copulation, and elicit changes in the mated female's behavior and physiology. Our previous studies showed that the injection of synthetic Drosophila melanogaster sex-peptide (DrmSP) into virgin females of the moth Helicoverpa armigera causes a significant inhibition of pheromone production. In this and other moth species, pheromone production, correlated with female receptivity, is under neuroendocrine control due to the circadian release of the neuropeptide PBAN. In this study, we show that PBAN, present in the hemolymph during the scotophase in females, is drastically reduced after mating. We also identify 4 DrmSP-like HPLC peaks (Peaks A, S1, S2, and B) in MAGs, with increasing levels of DrmSP immunoreactivity during the scotophase, when compared to their levels observed during the photophase. In H. armigera MAGs, a significant reduction in the pheromonostatic peak (Peak B) was already evident after 15 min of copulation, and depletion of an additional peak (Peak S2) was evident after complete mating. Peak A is also detected in female brains, increasing significantly 1 h after mating, at which time inhibition of pheromone biosynthesis also occurs. However, changes corresponding to the other MAG peaks were not detected in mated female tissues. Arch. Insect Biochem. Physiol. 64:142,155, 2007. © 2007 Wiley-Liss, Inc. [source]


Pathophysiological Mechanisms for Actions of the Neurotrophins

BRAIN PATHOLOGY, Issue 4 2006
Jeffery L. Twiss
Neurotrophins provide trophic and tropic support for different neuronal subpopulations in the developing and adult nervous systems. Expression of the neurotrophins and their receptors can be altered in several different disease or injury states that impact upon the functions in the central and peripheral nervous systems. The intracellular signals used by the neurotrophins are triggered by ligand binding to the cell surface Trk and p75NTR receptors. In general, signals emanating from Trk receptors support survival, growth and synaptic strengthening, while those emanating from p75NTR induce apoptosis, attenuate growth and weaken synaptic signaling. Mature neurotrophins are the preferred ligand for Trk proteins while p75NTR binds preferentially to the proneurotrophins and serves as a signaling component of the receptor complex for growth inhibitory molecules of central nervous system myelin [ie, myelin-associated glycoprotein (MAG), oligodendrocyte-myelin glycoprotein (OMgP) and Nogo]. The functional antagonism between Trk and p75NTR signaling may significantly impact the pathogenesis of human neurodevelopmental and neurodegenerative diseases and further complicate therapeutic uses of exogenous neurotrophins. The potential for each is discussed in this review. [source]


Consistent Bioactive Conformation of the Neu5Ac,(2,3)Gal Epitope Upon Lectin Binding

CHEMBIOCHEM, Issue 18 2008
Anirban Bhunia Dr.
Get to NOE MAG: Partial structures of GQ1b,, the natural ligand of the myelin-associated glycoprotein (MAG), have been synthesized and subjected to NOE experiments to determine their bioactive conformations. The experiments show that the flexible ,(2,3)-glycosidic linkage between N -acetylneuraminic acid and galactose present in all ligands adopts a "sialyl Lewisx -type" binding mode. This information is valuable for the future design of conformationally preorganized MAG inhibitors. [source]


Synthesis of Neu5Ac Oligosaccharides and Analogues by Transglycosylation and their Binding Properties as Ligands to MAG

CHEMBIOCHEM, Issue 6 2006
Björn Neubacher Dr.
Atrans -sialidase from Trypanosoma cruzi was used to prepare several sialic acid-containing oligosaccharides with a truncated glycerol side chain. STD NMR was used to characterise the binding constant and binding epitope of the oligosaccharides to their neural receptor protein MAG. [source]


Synthesis, radiolabeling and in vitro and in vivo characterization of a technetium-99m-labeled alpha-M2 peptide as a tumor imaging agent

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 6 2004
S.M. Okarvi
Abstract:, In an effort to develop a peptide-based radiopharmaceutical for the detection of breast cancer, we have prepared an analog of ,M2 peptide, modified to incorporate an N3S chelate system. Mercaptoacetyltriglycine (MAG)3 -derivatized ,M2 peptide was prepared by solid-phase synthesis and radiolabeled with 99mTc by an exchange method. In vitro cell-binding on human breast cancer cell lines, MDA-MB-231 and MCF-7, indicated the affinity and specificity of 99mTc-MAG3 - ,M2 toward breast cancer cells. Additionally, the radiolabeled peptide showed rapid internalization into human breast cancer cells. In vivo biodistribution in mice showed that the radiolabeled peptide cleared rapidly from the blood and most non-target tissues and was excreted significantly via the kidneys. Uptake of 99mTc-MAG3 - ,M2 in the tumor was moderate. The radiochemical and in vitro and in vivo characterization indicates that the radiolabeled peptide has certain favorable properties and it might be a useful radiopharmaceutical for the detection of breast cancer in vivo. [source]


Developing a hybrid emulsion polymerization system to synthesize Fe3O4/polystyrene latexes with narrow size distribution and high magnetite content

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2007
Longlan Cui
Abstract A hybrid emulsion polymerization was formulated for synthesizing Fe3O4/polystyrene composite latex. This system, containing binary droplets that are magnetic (Mag)-droplets with a diameter of 100,200 nm and styrene (St)-droplets with a diameter of 3,4 ,m, was obtained by mixing Mag-miniemulsion and St-macroemulsion. With extremely low surfactants concentration (,critical micelle concentration, CMC), the nucleated loci are selectively controlled in the Mag-droplets, as the result of smaller droplet size and larger surface ratio. Both water-soluble potassium persulfate (KPS) and oil-soluble 2,2,-azobis(2-isobutyronitrile) was adopted to initiate the polymerization. In the presence of KPS, magnetic polystyrene latices with particles size of 60,200 nm, narrow size distribution, and high magnetite content (86 wt % measured by TGA) were attained successfully. The synthesized magnetic Fe3O4/polystyrene latices assembled into well-ordered hexagonal structure in the surface of a carbon supported copper grid. The influence of various parameters on various aspects of the as-synthesized Fe3O4/polystyrene was investigated in detail: type of initiator on composite morphology, feed ratio of Mag-miniemulsion and St-macroemulsion on magnetite content, and hydrophobic agent or amount of surfactant on size and size distribution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5285,5295, 2007 [source]


High-stress plasticity and the core structures of dislocations in silicon

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2007
J. Rabier
Abstract The recent observation of perfect dislocations at high stress and low temperature in silicon [J. Rabier, P. Cordier, J. L. Demenet, and H. Garem, Mater. Sci. Eng. A 309/310, 74 (2001)] in accordance with the calculations of Duesbery and Joos [M. S. Duesbery and B. Joos, Philos. Mag. A 74, 253 (1996)] has solved the apparent paradox regarding the nature of mobile dislocations in silicon under usual deformation conditions. However, although several experiments and calculations are consistent with those perfect dislocations being located in the shuffle set, little is known about the actual core structure of those dislocations which lie along unusual Peierls valleys: ,112,/30°, ,123,/41°. This paper aims to review and discuss recent results related to high-stress plasticity and dislocation core structure in silicon. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Activation energy of thermally grown silicon dioxide layers on silicon substrates

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2009
G. Gerlach
Abstract A detailed numerical consideration is used as basic approach for calculating profiles of activation energy versus oxide thickness for various temperatures between 780 and 930,°C. Results presented here are intentionally not based on models of diffusion and reaction kinetics to avoid introducing correction terms due to the expansion of theory still under discussion. The statistical calculation gives the mean activation energy of 2.01,eV with standard deviation of 0.10,eV, very close to the overall activation energy of 2.05,eV [M. A. Rabie, Y. M. Haddara, and J. Carette, J. Appl. Phys. 98, 074904 (2005)]. More instructive features of the thermal oxidation of silicon have been disclosed directly from measurements of oxide thickness with time [M. A. Hopper, R. A. Clarke, and L. Young, J. Electrochem. Soc. 122, 1216 (1975) and J. Blanc, Philos. Mag. B 55, 685 (1987)]. Graphs of the natural logarithm of the growth rate versus oxide thickness, in the range between 2 and 65,nm, show that the oxide thickness influences the activation energy EA between 1.4 and 2.7,eV. [source]


Comparative activity and stability under salinity conditions of different antimicrobial peptides isolated from aquatic animals

AQUACULTURE RESEARCH, Issue 16 2009
Sara Emelie Löfgren
Abstract This study reports the in vitro activity of six antimicrobial peptides (AMPs) produced by aquatic animals (most marine invertebrates): tachyplesin (Tach), magainin (Mag), clavanin (Clav), penaeidin (Pen), mytilin (Myt) and antilipopolysaccharide factor (ALF) against marine vibrios, filamentous fungi and yeast. Their stability under salinity conditions and seawater was also examined. The results showed that Mag, Myt and especially Tach and ALF (minimum inhibitory concentration<1.5 ,M) had a potent activity against all tested vibrio species, whereas Clav and Pen were ineffective (up to 50 ,M). With respect to the antifungal activity, each AMP had a different potency according to the fungal species. In general terms, Tach was the most potent peptide, followed by Mag. Interestingly, Tach, Myt and ALF had a significant effect on the filamentous fungus Fusarium solani that could be pathogenic to marine organisms. All AMPs had a tendency to decrease or lose their activity at high salinity (>225 mM NaCl). Tach and Myt were the most stable peptides, maintaining significant activity under seawater salinity (450 mM). Curiously, all peptides lost their effect under seawater conditions. The results suggest that Tach, ALF and Myt are the most promising candidates for potential therapeutic use in farmed-marine species, because all have a significant and broad antimicrobial activity maintained at high salinity. [source]


Up-regulation of autophagy in small intestine Paneth cells in response to total-body ,-irradiation,,

THE JOURNAL OF PATHOLOGY, Issue 2 2009
Nikolai V. Gorbunov
Abstract Macroautophagy (mAG) is a lysosomal mechanism of degradation of cell self-constituents damaged due to variety of stress factors, including ionizing irradiation. Activation of mAG requires expression of mAG protein Atg8 (LC3) and conversion of its form I (LC3-I) to form II (LC3-II), mediated by redox-sensitive Atg4 protease. We have demonstrated upregulation of this pathway in the innate host defense Paneth cells of the small intestine (SI) due to ionizing irradiation and correlation of this effect with induction of pro-oxidant inducible nitric oxide synthase (iNOS). CD2F1 mice were exposed to 9.25 Gy ,-ionizing irradiation. Small intestinal specimens were collected during 7 days after ionizing irradiation. Assessment of ionizing irradiation-associated alterations in small intestinal crypt and villus cells and activation of the mAG pathway was conducted using microscopical and biochemical techniques. Analysis of iNOS protein and the associated formation of nitrites and lipid peroxidation products was performed using immunoblotting and biochemical analysis, and revealed increases in iNOS protein, nitrate levels and oxidative stress at day 1 following ionizing irradiation. Increase in immunoreactivity of LC3 protein in the crypt cells was observed at day 7 following ionizing irradiation. This effect predominantly occurred in the CD15-positive Paneth cells and was associated with accumulation of LC3-II isoform. The formation of autophagosomes in Paneth cells was confirmed by transmission electron microscopy (TEM). Up-regulation of LC3 pathway in the irradiated SI was accompanied by a decreased protein,protein interaction between LC3 and chaperone heat shock protein 70. A high-level of LC3-immunoreactivity in vacuole-shaped structures was spatially co-localized with immunoreactivity of 3-nitro-tyrosine. The observed effects were diminished in iNOS knockout B6.129P2- NOS2tm1Lau/J mice subjected to the same treatments. We postulate that the observed up-regulation of mAG in the irradiated small intestine is at least in part mediated by the iNOS signalling mechanism. Published in 2009 by John Wiley & Sons, Ltd. [source]


The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010
Tatsuki Ebisawa
Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2,Å crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants. [source]


Crystallization and preliminary X-ray analysis of a monomeric mutant of Azami-Green (mAG), an Aequorea victoria green fluorescent protein-like green-emitting fluorescent protein from the stony coral Galaxea fascicularis

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2009
Tatsuki Ebisawa
Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first monomeric green-emitting fluorescent protein that is not a derivative of Aequorea victoria green fluorescent protein (avGFP). mAG and avGFP are 27% identical in amino-acid sequence. Diffraction-quality crystals of recombinant mAG were obtained by the sitting-drop vapour-diffusion method using PEG 3350 as the precipitant. The mAG crystal diffracted X-rays to 2.20,Å resolution on beamline AR-NW12A at the Photon Factory (Tsukuba, Japan). The crystal belonged to space group P1, with unit-cell parameters a = 41.78, b = 51.72, c = 52.89,Å, , = 90.96, , = 103.41, , = 101.79°. The Matthews coefficient (VM = 2.10,Å3,Da,1) indicated that the crystal contained two mAG molecules per asymmetric unit. [source]


GMO Food Labelling in the EU: Tracing ,the Seeds of Dispute'

EUROCHOICES, Issue 1 2003
Maria L. Loureiro
Summary GMO Food Labelling in the EU: Tracinq ,the Seeds of Dispute' Genetically modified (GM) food labelling has become a critical issue in the international trade arena. Policymakers and consumers in the European Union (EU) seem to agree on the need to control the use of biotechnology in the food industry. As a consequence, recently the EU Commission approved a measure that establishes strict rules on genetically modified organisms (GMOs), but which lifts the moratorium on GMO production and marketing. This new Directive deals with mandatory labelling of GM foods and their traceability along the food chain. In spite of the substantial effort made to reconcile the different opinions in the escalating debate about biotechnology, the new GMO regulation seems to be unsatisfactory for too many interest groups. A system of total traceability from ,farm to fork' and mandatory labelling for genetically modified products may be considered too complex and too expensive to implement, particularly by those countries or industries that have produced GMO foods for many years. Yet, giving European consumers the freedom to choose GMOs may be the only option that there is until Europeans restore their confidence in the food system and food regulators. A market or consumer-driven solution may eventually terminate the GMO dispute between the two transatlantic trading blocks. , Assurance , Revenud a ns , Agriculture Européenne ,étiquetage des aliments contenant des organismes génétiquement modifyés (OGM) est devenu une question cruciale sur la scène du commerce international. Tant les décideurs politiques que les citoyens de , Union européenne semblent s'accorder sur la nécessité de soumettre à contrôle , utilisation des biotechnologies dans , industrie alimentaire. En conséquence, la Commission européenne a récemment approuvé une mesure qui établit des règies strictes sur les OGM, mais qui lève le moratoire sur leur production et leur commercialisation. Cette nouvelle directive concerne ,étiquetage obligatoire des aliments contenant des OGM et la façon ? en assurer le suivi dans les filières alimentaires. Ce nouveau règlement OGM, en dépit des efforts réels effectués pour réconcilier les différents points de vue dans la montée du débat sur les biotechnologies, semble inconciliable avec trop de groupes ? intérêts pour être satisfaisant. Un système assurant une traçabilité totale, ,du champ à la fourchette' et un étiquetage obligatoire pour tout produit contenant des OGM, paraît bien trop complexe et coûteux à mettre en ,uvre, en particulier pour les pays ou les industries qui produisent des aliments génétiquement modifyés depuis des années. Et pourtant, il se pourrait bien que la seule façpn de restaurer la confiance perdue des Européens dans le système alimentaire et ses institutions soit justement de leur donner le droit de choisir. La fin de la querelle des OGM entre les blocs commerciaux des deux rives de , Atlantique peut venir de solutions apportées par le marché et issues des consommateurs. Einkommenversicherung in der Europäischen Landwirtschaft Die Kennzeichnung von genetisch veränderten Lebensmitteln ist zu einer der bedeutendsten Streitfragen auf dem Gebiet des internationalen Handels geworden. Politische Entscheidungsträger und Verbraucher in der Europäischen Union scheinen dahingehend überein zu stimmen, dass der Einsatz von Biotechnologie in der Nahrungsmittel-industrie kontrolliert werden sollte. Als Reaktion darauf hat die EU-Kommission kürzlich einer Maßnahme zugestimmt, welche ein strenges Regelwerk für genetisch veränderte Organismen (GVO) festschreibt, mit der aber gleichzeitig das Moratorium für die Produktion und Vermarktung von GVO aufgehoben wird. Die neue Richtlinie beschäftigt sich mit der Pflichtkennzeichnung von genetisch veränderten Nahrungsmitteln und mit ihrer Rückverfolgbarkeit entlang der Nahrungsmittelkette. Trotz der erheblichen Anstrengungen, die verschiedenen Standpunkte in der eskalierenden Debatte um Biotechnologie zu berücksichtigen, scheint die neue GVO Richtlinie in den Augen (zu) vieler Interessengruppen unbefriedigend zu sein. Ein System der vollständigen Rückverfolgbarkeit vom Stall bis zum Teller und die Pflichtkennzeichnung von genetisch veränderten Nahrungsmitteln mag in der Umsetzung als zu komplex und zu teuer betrachtet werden, insbesondere von den Ländern oder Industriezweigen, welche seit vielen Jahren GVO-Nahrungsmittel hergestellt haben. Dennoch könnte der Ansatz, den europäischen Verbrauchern die freie Wahl für oder gegen GVO zu gewähren, der einzig gangbare Weg sein, bis die Europäer ihr Vertrauen in das Produktions- und Kontrollsystem für Nahrungsmittel zurückgewonnen haben. Eine markt- oder verbraucherorientierte Lösung könnte letztlich den Streit um GVO zwischen den beiden transatlantischen Handelsblöcken beenden. [source]


Pycnogonid affinities: a review

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 1 2005
J. A. Dunlop
Abstract Early authors regarded Pycnogonida (sea spiders) either as aquatic arachnids, ,degraded' crustaceans or as some sort of intermediate form between the two. Subsequently, pycnogonids were either placed among the Chelicerata or considered as an isolated group, unrelated to other arthropods. The latter model is untenable under phylogenetic systematics and recent cladistic studies have supported one of two alternative hypotheses. The first is the traditional Chelicerata s.lat. concept, i.e. (Pycnogonida + Euchelicerata). This, however, has only one really convincing synapomorphy: chelate chelicerae. The second hypothesis recognizes (Pycnogonida + all other Euarthropoda) and has been recovered in various ,total evidence' studies. Morphologically some characters , the presence of gonopores on the trunk and absence of a labrum, nephridia and intersegmental tendons , support Cormogonida (Euarthropoda excluding pycnogonids). Advances in developmental biology have proposed clear interpretations of segmentation homologies. However, so far there is also a confrontation of the two hypotheses depending on whether the last walking leg segment is considered part of the prosoma. In this case pycnogonids have too many prosomal segments compared with Euchelicerata; perhaps implying they are not sister groups. Alternatively, if part of the postprosomal region, the last leg pair could correspond to the chilarial segment in euchelicerates and its uniramous state could be apomorphic with respect to other euarthropods. Molecular phylogenies need to be more rigorously analysed, better supported by data from different sources and technique-sensitive aspects need to be explored. Chelicerata s.lat. may emerge as the more convincing model, yet even the putative autapomorphy of chelicerae needs to be treated with caution as there are fossil ,great appendage' arthropods in the early Palaeozoic which also have a robust, food-gathering, pair of head limbs and which may lie on the chelicerate, or even the euarthropod, stem lineage. Zusammenfassung Frühere Autoren betrachteten die Pycnogonida (Asselspinnen) entweder als wasserbewohnende Spinnentiere oder als rückgebildete Krebstiere oder als eine Zwischenform zwischen den beiden Gruppen. Später wurden die Pycnogonida entweder den Chelicerata zugeordnet oder als eine isolierte Gruppe, die mit den anderen Arthropoden in keiner Verwandtschftsbeziehung steht, betrachtet. Die letztere Annahme ist unter den Aspekten der phylogenetischen Systematik unbrauchbar. Neue cladistische Untersuchungen unterstützen zwei verschiedene, alternative Hypothesen: die erste Hypothese entspricht dem traditionellen Chelicerata s. lat.-Konzept, d.h. Pycnogonida + Euchelicerata bilden eine Gruppe. Hier gibt es aber nur eine einzige überzeugende Synapomorphie: klauenartige Cheliceren. Die zweite Hypothese anerkennt eine Gruppierung (Pycnogonida + alle anderen Euarthropoda), entsprechend den Ergebnissen verschiedener ,,Total Evidence-Analysen''. Einige morphologische Merkmale, wie das Auftreten von Gonoporen am Rüssel, das Fehlen des Labrums, der Nephridien und der intersegmentalen Sehnen, unterstützt das Taxon Cormogonida (alle Euarthropoda mit Ausschluß der Pycnogonida). Fortschritte in der Entwicklungsbiologie erlauben jetzt eine klare Homologisierung der Segmente. Es besteht jedoch weiterhin ein Konflikt zwischen den beiden Hypothesen bezüglich der Frage, ob das letzte Laufbeinsegment ein Teil des Prosomas ist. In letzterem Fall hätten die Pycnogonida im Vergleich mit den Euchelicerata zu viele prosomale Segmente; vielleicht kann das als Hinweis angesehen werden, daß die beiden Taxa keine Schwestergruppen sind. Alternativ, wenn das letzte Laufbeinsegment ein Teil der post-prosomatischen Region ist, könnte es dem chilarialen Segment der Euchelicerata in seinem einstrahligen Zustand entsprechen und eine Apomorphie gegenüber den anderen Euarthropoden darstellen. Die molekularen Phylogeniestudien müssen strenger analysiert, besser durch Daten von anderer Seite unterstützt und die Aspekte der Empfindlichkeit der technischen Methoden besser untersucht werden. Das Chelicerata s. lat.- Modell mag als das mehr überzeugende erscheinen, doch müssen die vermutlichen Autoapomorphien der Chelicerata mit Vorsicht behandelt werden, denn es gibt da die fossilen Gliederfüßler aus dem frühen Paläozooikum, die sogenannten ,,great appendage'' - Euarthropoden mit einem großen robusten Paar von Kopfgliedern als Fangapparat, die nahe bei den Chelicerata stehend oder sogar als Stammgruppe der Euarthropoden angesehen werden können. [source]


A model for saturation correction in meteor photometry

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2010
Jean-Baptiste Kikwaya
ABSTRACT In order to correct for the effect of saturation on photometric measurements of meteors, we have developed a numerical model for saturation and apply it to data gathered using two generation III image intensified video systems on two nights (2008 October 31 and 2008 November 6). The two cameras were pointed in the same direction, and the aperture of one camera was set two stops below the aperture of the other. With these conditions, some meteors saturated one camera but not the other (group I); some saturated both cameras (group II); and some did not saturate either of them (group III). A model of meteor saturation has been developed which uses the image background value, angular meteor speed and the lateral width of the meteor image to simulate the true and saturated light curve of meteors. For group I meteors, we computed a saturation correction and applied it to the saturated light curve. We then compared the corrected saturated curve to the unsaturated curve from the other camera to validate the model. For group II meteors, a saturation correction is calculated and applied to both observed light curves, which have different degrees of saturation, and the corrected curves are compared. We collected 516 meteors, of which 30 were of group I, and seven of group II. For meteors in group I, an average residual of less than 0.4 mag was found between the observed unsaturated light curve and the model-corrected saturated light curve. For meteors in group II, the average residual between the two corrected light curves was 0.3 mag. For our data, the saturation correction goes from 0.5 to 1.9 mag for meteors in group I, and 1.2 to 2.5 mag for meteors in group II. Based on the agreement between the observed and modelled light curves (less than 0.4 mag over all meteors of all groups), we conclude that our model for saturation correction is valid. It can be used to extract the true luminosity of a saturated meteor, which is necessary to calculate photometric mass. Our model also demonstrates that fixed corrections to saturated meteor photometry, not accounting for background levels or angular velocities, do introduce significant error to meteor photometric analyses. [source]


An HST/ACS view of the inhomogeneous outer halo of M31,

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2009
J. C. Richardson
ABSTRACT We present a high precision photometric view of the stellar populations in the outer halo of M31, using data taken with the Hubble Space Telescope/Advanced Camera for Surveys. We analyse the field populations adjacent to 11 luminous globular clusters which sample the galactocentric radial range 18 ,R, 100 kpc and reach a photometric depth of ,2.5 mag below the horizontal branch (mF814W, 27 mag). The colour,magnitude diagrams are well populated out to ,60 kpc and exhibit relatively metal-rich red giant branches, with the densest fields also showing evidence for prominent red clumps. We use the Dartmouth isochrones to construct metallicity distribution functions which confirm the presence of dominant populations with ,[Fe/H],,,0.6 to ,1.0 dex and considerable metallicity dispersions of 0.2 to 0.3 dex (assuming a 10 Gyr population and scaled-solar abundances). The average metallicity over the range 30,60 kpc is [Fe/H]=,0.80 ± 0.14 dex, with no evidence for a significant radial gradient. Metal-poor stars ([Fe/H],,1.3) typically account for ,10,20 per cent of the population in each field, irrespective of radius. Assuming our fields are unbiased probes of the dominant stellar populations in these parts, we find that the M31 outer halo remains considerably more metal rich than that of the Milky Way out to at least 60 kpc. [source]


The stellar population content of the thick disc and halo of the Milky Way analogue NGC 891

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2009
M. Rejkuba
ABSTRACT We present deep VI images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope, covering three fields in the north-east side of the edge-on disc galaxy NGC 891. The observed fields span a wide range of galactocentric distances along the eastern minor axis, extending from the plane of the disc to 12 kpc, and out to ,25 kpc along the major axis. The photometry of individual stars reaches ,2.5 mag below the tip of the red giant branch. We use the astrophotometric catalogue to probe the stellar content and metallicity distribution across the thick disc and spheroid of NGC 891. The colour,magnitude diagrams of thick disc and spheroid population are dominated by old red giant branch stars with a wide range of metallicities, from the sparsely populated metal-poor tail at [Fe/H],,2.4 dex, up to about half-solar metallicity. The peak of the metallicity distribution function of the thick disc is at ,0.9 dex. The inner parts of the thick disc, within ,14 kpc along the major axis show no vertical colour/metallicity gradient. In the outer parts, a mild vertical gradient of ,(V,I)0/,|Z| = 0.1 ± 0.05 kpc,1 or less than 0.1 dex kpc,1 is detected, with bluer colours or more metal-poor stars at larger distances from the plane. This gradient is, however, accounted for by the mixing with the metal-poor halo stars. No metallicity gradient along the major axis is present for thick-disc stars, but strong variations of about 0.35 dex around the mean of [Fe/H]=,1.13 dex are found. The properties of the asymmetric metallicity distribution functions of the thick-disc stars show no significant changes in both the radial and the vertical directions. The stellar populations situated within the solar-cylinder-like distances show strikingly different properties from those of the Galaxy populating similar distances. This suggests that the accretion histories of both galaxies have been different. The spheroid population, composed of the inner spheroid and the halo, shows remarkably uniform stellar population properties. The median metallicity of the halo stellar population shows a shallow gradient from about ,1.15 dex in the inner parts to ,1.27 dex at 24 kpc distance from the centre, corresponding to ,13reff. Similar to the thick-disc stars, large variations around the mean relation are present. [source]


Spectroscopic and photometric observations of the selected Algol-type binaries , II.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008
V2080 Cygni, V2365 Ophiuchi
ABSTRACT This paper is the second in the planned series of investigations. We present new radial velocities and photometric observations of V2080 Cyg and V2365 Oph. New UBV photometric data and radial velocities were analysed for the systems' parameters. While V2080 Cyg consists of two nearly equal F-type main-sequence stars, V2365 Oph has two different components, namely an early A-type primary and a G-type secondary star. New ephemerides are calculated for both systems. The masses of the component stars have been derived as 1.19 ± 0.02 and 1.16 ± 0.02 M, for V2080 Cyg and 1.97 ± 0.02 and 1.06 ± 0.01 M, for V2365 Oph. The effective temperatures and reddening of the systems have been estimated from Johnson wide-band UBV photometric calibrations. The radii have been measured by simultaneous fitting the UBV light curves using Wilson,Devinney code and are 1.60 ± 0.01 R, for both components of V2080 Cyg and 2.19 ± 0.01 and 0.934 ± 0.004 R, for V2365 Oph. The absolute parameters of the stars in both systems lie within the same ranges in the mass,radius, mass,effective temperature, mass,luminosity and luminosity,effective temperature planes as in detached Algol systems. A comparison between the properties of the systems of interest and the predictions of theoretical evolutionary models is undertaken in the log g,logTeff, log R, log M and radius,log age diagrams. The model predictions match the measured properties of V2080 Cyg for an age of about 5.6 Gyr and a ,solar' metal abundance (Z= 0.019), indicating the components near the end of their core hydrogen-burning phases. However, the position of the components of V2365 Oph on the Hertzsprung,Russell (HR) diagram is best reproduced with evolutionary models for somewhat metal-deficient (Z= 0.004) stars. We found an age of about 700 Myr, with the primary component slightly evolved off the zero-age main-sequence and the secondary one still very close to it. From the basic stellar parameters we have also redetermined the distances to V2080 Cyg and V2365 Oph as 78 ± 1 and 251 ± 8 pc, which are in agreement with, and more accurate than, Hipparcos values. The observations show that at least one of the components of V2365 Oph is an intrinsic variable with a period and peak-to-peak amplitude of 0.07 d and 0.05 mag, respectively. In accordance with its position in the HR diagram, the primary component should be considered as a , Scuti star and it is believed to be the variable star in the system. [source]


Discovery of new nearby L and late-M dwarfs at low Galactic latitude from the DENIS data base

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2008
N. Phan-Bao
ABSTRACT We report on new nearby L and late-M dwarfs (dphot, 30 pc) discovered in our search for nearby ultracool dwarfs (I,J, 3.0, later than M8.0) at low Galactic latitude (|b| < 15°) over 4800 deg2 in the Deep Near Infrared Survey of the Southern Sky (DENIS) data base. We used late-M (, M8.0), L and T dwarfs with accurate trigonometric parallaxes to calibrate the MJ versus I,J colour,luminosity relation. The resulting photometric distances have standard errors of ,15 per cent, which we used to select candidates dphot, 30 pc. We measured proper motions from multi-epoch images found in the public archives ALADIN, DSS, 2MASS and DENIS, with at least three distinct epochs and time baselines of 10,21 yr. We then used a maximum reduced proper motion cut-off to select 28 candidates as ultracool dwarfs (M8.0,L8.0) and to reject one as a distant red star. No T dwarf candidates were found in this search, which required an object to be detected in all three DENIS bands. Our low-resolution optical spectra confirmed that 26 were indeed ultracool dwarfs, with spectral types from M8.0 to L5.5. Two contaminants and one rejected by the maximum reduced proper motion cut-off were all reddened F,K main sequence stars. 20 of these 26 ultracool dwarfs are new nearby ultracool dwarf members, three L dwarfs within 15 pc with one L3.5 at only ,10 pc. We determine a stellar density of dwarfs pc,3 mag,1 over 11.1 ,MJ, 13.1 based on this sample of M8,L3.5 ultracool dwarfs. Our ultracool dwarf density value is in good agreement with the measurement by Cruz et al. of the ultracool dwarf density at high Galactic latitude. [source]